module.exports = (totalSize,req,res) => {
  const range = req.headers['range'];
  if(!range){
    return{code:200};
  }

  const sizes = range.match(/bytes=(\d*)-(\d*)/);
  const end = sizes[2] || totalSize - 1;
  const start = sizes[1] || totalSize - end;

  if(start > end || start < 0 || end > totalSize){
    return {code:200};
  }
  res.setHeader('Accept-Ranges','bytes');
  res.setHeader('Content-Range',`bytes ${start}-${end}/${totalSize}`);
  res.setHeader('Content-Length',end - start);
  return{
    code:206,
    start:parseInt(start),
    end:parseInt(end)
  }
}
